Environmental enclosures are used by hospitals, animal testing facilities, chemical plants, and the like to maintain a germ-free or defined flora atmosphere. In some instances the environmental enclosure may be a small table top unit adapted to hold up to one dozen animals in a germ-free atmosphere. In other instances the enclosure may constitute a walk-in chamber or clean room of substantial size to permit the operator to walk and work within the enclosure.
One common form of clean room includes a flexible drape which extends downwardly from the ceiling and defines the clean room or chamber. In installations of this type, filtered air is introduced through the ceiling into the chamber and is discharged through the space beneath the drape for recirculation through the filter.
Another type of commonly used clean room is the fixed wall or permanent type and the clean atmosphere is achieved by circulating filtered air through the room. The permanent type clean room is extremely expensive to construct, and cannot be readily adapted for other types of usage.
In use, operators must periodically enter the clean room to inspect or tend the animals or other objects being controlled. To maintain the sterile atmosphere in the clean room, the normal procedure is for the operator to shower and put on sterile garments before entering the clean room. While this procedure is intended to maintain the sterile conditions, in practice, it is not completely effective in preventing contamination of the clean room.
As an additional problem, the clean room may contain toxic or hazardous microorganisms and in the past there has been no completely foolproof method of preventing the operator, during periods of entry into the clean room, from being contaminated with the hazardous materials, thus posing a potential health hazard to the operator and a threat of contamination to the surrounding environment.